WO2012171624A1

WO2012171624A1 - Centrifuge having compressor cooling

Info

Publication number: WO2012171624A1
Application number: PCT/EP2012/002435
Authority: WO
Inventors: Heiko Müller; Sven Fischer
Original assignee: Eppendorf Ag
Priority date: 2011-06-14
Filing date: 2012-06-08
Publication date: 2012-12-20
Also published as: US20130298577A1; CN103153476B; EP2600978A1; US8974361B2; DE102011105878A1; JP2014522315A; US20130219926A1; JP5829333B2; CN103153476A; EP2600978B1

Abstract

The present invention relates to a centrifuge (10) and a method for cooling a centrifuge (10). The centrifuge (10) of the invention has a cooler (11, 14, 15) improved to the extent that the space requirement thereof is reduced, such that the centrifuge (10), for the same centrifuging capacity, can be kept more compact, or, for the same structural dimensions, the centrifuging capacity can be increased. In addition, savings in components, and thereby savings in costs and assembly time, are permitted.

Description

Centrifuge with compressor cooling

The present invention relates to a centrifuge, in particular a laboratory centrifuge, according to the preamble of claim 1 and a method for cooling a centrifuge according to the preamble of claim 12.

During centrifugation, heat is generated during the rotation of the centrifuge rotor in the centrifuge vessel due to air friction and electrical power loss. Since the centrifuge bowl is closed with a lid to prevent spillage of centrifuging, this heat input can not be easily removed and leads to an increase in the temperature of the centrifuged.

However, this temperature increase is undesirable because it can lead to destruction or uselessness of the centrifuged samples. Usually, the samples must be kept at a defined temperature, for example, depending on the application to temperatures of 4 ° C, 22 ° C or 37 ° C. Therefore, precautions have been taken in the past to avoid increasing the temperature of the centrifuged. This can be done either by direct cooling or by indirect cooling by means of a heat exchanger principle. In the case of direct cooling (indirect cooling), there is no direct contact between the cooling medium and the material to be cooled or the coating of the material to be cooled.

In direct cooling, the ambient air is passed directly through the centrifuge bowl at the centrifuge rotor, with the rotor acting as a kind of radial fan. For this purpose, the centrifuge lid and / or centrifuge bowl has an inlet opening near the axis and an outlet opening arranged at a distance from the axis of rotation. Although such direct cooling has proven itself, the centrifuge tank must have an outlet opening for it, which, however, also permits a material outlet. A disadvantage of the direct cooling results from the use of ambient air as a coolant: the sample can be cooled to a maximum of only the temperature of the ambient air.

CONFIRMATION COPY In indirect cooling, the rotor is enclosed in the centrifuge vessel under the centrifuge lid and no cooling channel or the like is provided. The air circulates therefore only within the centrifuge bowl. Cooling is now achieved by a second medium, which is passed on the outside of the boiler. This can either be ambient air, which is conducted past the outside of the boiler, as is realized, for example, in the case of the centrifuge 5424 from Eppendorf AG. Alternatively, the cooling device consists of a compressor cooling with tubes and heat exchangers which are arranged above the device-side base plate, wherein a special coolant via pipes, for example, spirally on the boiler, ie the side walls and the bottom of the boiler, abuts, is passed to the boiler to remove heat. In the latter variant of the indirect cooling and cooling of the sample material to a temperature below the temperature of the ambient air is possible. An advantage of indirect cooling is the better controllability of the temperature to be set compared to direct cooling.

The base plate of the centrifuge, which is usually made of metal, is used in prior art centrifuges only for the passive removal of a portion of the heat from the interior of the housing.

But even when running in vacuum rotors, in so-called ultracentrifuges, this principle of passive cooling is used on the base plate, as disclosed for example in DE 23 43 070 AI.

The object of the present invention is to further improve the active indirect cooling of centrifuges. In particular, the space requirement should be reduced, so that the centrifuges can be kept more compact at the same Zentrifugierkapazität or centrifuging capacity can be increased with the same dimensions. In addition, a saving of components and thus a saving of costs and assembly time should be made possible in particular. This object is achieved with the centrifuge according to claim 1 and the cooling method according to claim 12. Advantageous developments are specified in the dependent subclaims.

The inventors have recognized that in modern centrifuges can be dispensed with a separate condenser or gas cooler for the cooling medium of the compressor cooling when the base plate itself is used as a heat exchanger for the coolant to dissipate the heat. In the case of the gas cooler heat is not dissipated by the condenser, but in a transcritical process, sensible heat is released from the hot gas. In the case of the condenser, on the other hand, a phase transformation takes place via three processes: the defrosting of the hot gas, the liquefaction and the subcooling of the liquid refrigerant. From the basic structure as a component condenser and gas cooler are the same design and need to be designed according to the particular application. Therefore, in the following uniformly spoken of liquefier, although gas coolers are included.

So far, while the base plate for passive cooling, i. to dissipate the heat from the electronics of the centrifuge, it is now part of a compressor cooling and thus an active cooling of the centrifuge. In this case, the cooling medium flowing from the compressor, which may have a temperature of up to 120 ° C, depending on the ambient temperature to temperatures of about 35 ° C (at an ambient temperature of about 20 ° C) cooled. By dispensing with the usual condenser compressor cooling additional space is available laterally / in front of / behind the rotor, because such condenser were always arranged there. This additional space can now be used for housing the control electronics, which should not be located below the rotor, pipes or other parts of the Käteanlage because of the risk of condensation.

For the centrifuge, in particular laboratory centrifuge, which has a centrifuge rotor, a centrifuge motor, a compressor cooling device and a machine frame with a base plate, it is therefore provided according to the invention that the base plate is in heat-conducting connection with the compressor cooling device such that the base plate forms a heat exchanger of the compressor cooling device and thus acts at least as part of a condenser for the cooling medium of the compressor cooling device.

By this configuration can be dispensed with a separate condenser and its space is not needed, resulting in Baumaßvorteile the centrifuge according to the invention over previous designs. Alternatively, of course, the centrifuging capacity can be increased while maintaining the same structural dimensions. In addition, the costs and installation costs are reduced.

In an expedient embodiment it is provided that a conduit means for the coolant is provided on and / or in the base plate, wherein the conduit means is preferably formed as a tube. In this case, the base plate as a condenser structurally very simple design. In addition, can be ensured by the formation of a pipe optimal tightness and the flow in a pipe runs optimally and can be made particularly resistant, which would otherwise lead to pressure drop and thus to a deterioration of the cooling.

In this context, it is preferred if the conduit means is cast into the base plate or that the base plate is constructed at least in two parts and the conduit means arranged in the parting plane between the two parts, in particular in at least one part is incorporated. For example, the conduit means may be cast into the base plate, in particular using a copper tube which is cast into the aluminum base plate. Alternatively, a sandwich construction can take place, in which case a relatively high accuracy of fit has to be ensured in order to prevent leaks. Alternatively, an inserted pipeline can also be used in the sandwich construction in order to prevent leaks. Again, a high accuracy of fit is required so that an optimal heat transfer between the pipe and the sandwich parts of the base plate is guaranteed, otherwise obstructed air or the like heat transfer. To exclude this, a means for improving the heat transfer, for example a thermal compound, between the pipeline and sandwich parts of the base plate is preferably arranged. It is particularly advantageous if the base plate has at least one surface-enlarging element, in particular one or more cooling ribs, on at least one of the two major main surfaces. Then, the base plate can give off the heat of the coolant particularly well, because its surface is advantageously increased for cooling and optionally can be used in an active cooling of the base plate to reduce noise with a slow / low air flow. In addition, these cooling fins can also be used expediently for an airflow duct of active cooling. For these elements, no separate space must be provided, as due to the bearing plate between the base plate and boiler enough space is available and even below the base plate is such space available.

Furthermore, it can be advantageously provided that the base plate has at least one opening which is not in fluid communication with the conduit means. As a result, passively or actively generated air flows can be very well steered, because such an air flow can now also pass through the base plate itself. In a particularly preferred embodiment, such breakthroughs are used to selectively interrupt or reduce the thermal conductivity of the base plate, thereby separating the warm input from the cold outlet in the condenser and thus to increase its effectiveness.

Even if passive cooling of the base plate by means of suitable air flow guidance, inter alia with the help of the surface enlarging elements is quite possible to avoid a heat build-up within the centrifuge particularly expedient active cooling of the base plate is provided by means of at least one ventilation means. In this case, the ventilation means, such as a fan, is in operative connection with the base plate and is preferably adapted to generate an air flow in the housing of the centrifuge, which enters the housing laterally and / or on the bottom side. To increase fire safety, an air-permeable cover of ventilation openings can be provided in the housing In addition, this ventilation means is particularly effective in removing heat generated by the engine and drive electronics created in the boiler room by air resistance introduced by the samples to be centrifuged themselves or by centrifugation, and heat from outside, for example, penetrates through the lid in the centrifuge. This venting means thus provides significant support to the compressor cooling.

In order to prevent contact with hot parts of the centrifuge, it may be provided that the base plate is arranged on the housing of the centrifuge that the heat transfer between the base plate and the housing is interrupted or at least reduced. For this purpose, a heat-insulating connection is preferably arranged between the base plate and the housing of the centrifuge.

Self-contained protection is claimed for the inventive method for cooling a centrifuge, in particular a laboratory centrifuge, wherein a compressor cooling device is provided, which is characterized in that a base plate of the centrifuge is used at least as part of a condenser of the compressor cooling device.

It is particularly advantageous if a ventilation means is provided which generates an air flow parallel to and / or ascending through the base plate. This creates a particularly effective active cooling of the base plate so that it acts particularly effectively as a condenser.

In the method according to the invention, the centrifuge according to the invention is particularly suitably used.

The characteristics of the present invention and further advantages will be apparent from the description of preferred embodiments in conjunction with the figures. Showing:

Fig. 1 is a plan view of a centrifuge with condenser according to the prior

Technology without housing components,

2 is an overall perspective view of the centrifuge of FIG. 1, a top view of the centrifuge according to the invention without housing components,

different overall perspective views of the centrifuge according to the invention according to FIG. 3,

the base plate for the centrifuge according to the invention according to FIG. 3 in a first preferred embodiment in a perspective view from above,

the base plate for the centrifuge according to the invention according to FIG. 3 in the first preferred embodiment in a perspective view from below,

the base plate for the centrifuge according to the invention according to FIG. 3 in a first preferred embodiment in a plan view,

the base plate for the centrifuge according to the invention according to FIG. 3 in the first preferred embodiment in section,

the base plate for the centrifuge according to the invention according to FIG. 3 in a second preferred embodiment as a sandwich base plate with the upper part in a perspective view from above,

the base plate for the centrifuge according to the invention according to FIG. 3 in the second preferred embodiment as a sandwich base plate with the upper part in a perspective view from below,

3 in the second preferred embodiment as a sandwich base plate with the lower part in a perspective view from below,

the base plate for the centrifuge according to the invention of FIG. 3 in the second preferred embodiment as a sandwich base plate with the lower part in a perspective view from above and the base plate for the centrifuge according to the invention of FIG. 3 in the second preferred embodiment in section.

In Fig. 1 is shown purely schematically in a partial plan view of a known from the prior art laboratory centrifuge 1, in addition to the electronics 2, the centrifuge vessel 3 and the underlying motor (not shown), the centrifuge rotor 4, the compressor 5 and the base plate 6 has a condenser 7. Between compressor 5 and condenser 7, a fan 8 for the condenser 7 is arranged. In Fig. 2, this known centrifuge 1 is shown in perspective together with the housing 9 and cover 9a.

In Fig. 3, the centrifuge 10 according to the invention is shown purely schematically in a preferred embodiment in the partial plan view. In Fig. 4a, 4b, the centrifuge 10 according to the invention is shown in different perspective views.

It can be seen that the centrifuge 10 has a base plate 1 1 and a vessel 12 with centrifuge rotor 13, wherein on the base plate 1 1 below the boiler via its bearing plate of the centrifuge motor (bearing shield and centrifuge motor form in a manner known to those skilled in a unitary component and are not shown separately). The centrifuge 10 has a compressor cooling 14 with a coolant line 15 which is guided through the base plate 11. Furthermore, the centrifuge 10 control electronics 16 and two fans 17, the air via vents 18 in the base plate 1 1 and arranged in the housing 19 vents 20 air in the housing 19 and discharges through ventilation slots 21 from the housing 19.

In FIGS. 5 to 8 and FIGS. 9 to 13, two different preferred embodiments of the base plate I I a, I I b are shown in more detail.

In the first preferred embodiment of FIG. 5 to 8 is a base plate I I a, which is formed in two parts, wherein for the preparation of this base plate I Ia in the casting process, a pipe 22 has been poured into the base plate body 23. As a result, an ideal heat transfer is achieved by material connection. On the other hand, there is no danger of leaks and the like. Therefore, this training is particularly safe. The pipe 22 is preferably made of copper while the base plate body 23 is preferably cast of aluminum.

Also visible are an opening 25 and attachment points 26 for receiving and mounting of bearing plate and centrifuge motor (both not shown). Except- the fastening points 27 are provided for fastening the compressor cooling 14 and connection points 28, 29 for connecting the pipe 22 to the compressor cooling 14. Both on the top 30 and on the bottom 31 cooling fins 32, 33 are provided, which are arranged parallel to each other and a Define air flow direction.

In the second preferred embodiment of FIGS. 9 to 13 is a base plate I Ib, which is formed in several parts, wherein the base plate I Ia consists of an upper part 40 and a lower part 41. Both were manufactured using the casting process and have the formations 42, 43 for a pipeline. However, instead of cast parts 40, 41, these can also be produced by milling and the like. By screwing, gluing or welding or other means of connection of the two base plate parts 40, 41 results in an integrally formed base plate I Ib in which there is also material connection. In order to prevent the risk of leaks and the like, it is necessary to work very precisely here. Alternatively, a separate pipe between the plates can be inserted. In this case, a means for improving the heat transfer, for example a thermal compound, is preferably provided between the parts of the base plate and the inserted pipeline. Also in this case, a very exact configuration of the formations and the tube is required to ensure good heat transfer between the pipe and the sub-plates of the base plate.

Also in the base plate I Ib are an opening 25 and attachment points 26 for receiving and mounting of bearing plate and centrifuge motor (not shown) and both on the top 44 and bottom 45 of the base plate 1 l b are ribs 46, 47 in turn arranged parallel to each other. For connection to the compressor cooling 14 ports 48, 49 are provided. In Fig. 13 is specifically seen that the upper part 40 is inserted into the lower part 41 and that the pipe 50 is located in the parting plane T.

The ventilation slots 18 arranged in the base plate 1 1, II a, II b serve not only as openings for the passage of air but also for separating warmer and colder zones in the base plate 11, IIa, 11b, the warmer zone being the who is inside, while the colder zone at the edge of the base plate 1 1, II a, II b runs. Connection point 29 thus feeds the warmer zone and connection point 28 is used for removal from the colder zone.

In the operating state of the centrifuge 10, the base plate 1 1, I I a, I I b serves as a heat exchanger surface and thus acts for the guided through the coolant line 22, 50 coolant the compressor cooling 14 as condenser 51, 51 a, 51 b. The base plate 1 1, I I a, I I b takes on the heat of the coolant and gives it over their means of the ribs 32, 33, 46, 47 extended surface 30, 31, 44, 45 from. These ribs 32, 33, 46, 47 also generate in connection with the fan 17 an air flow, which dissipates the heat to the outside and thus the centrifuge 10 cools overall. The base plate 1 1, I I a, I Ib is arranged in the centrifuge 10 so that there is no direct thermal contact with the housing 19. The openings 18, 20, 21 are also covered with a gauze (not shown) or the like, so that fire protection requirements is satisfied.

While the base plate 11 according to the invention, I I a, I I b ribs 32, 33, 46, 47, which are aligned parallel to each other, are basically also angular, i. 180 ° deviating arrangements to each other possible. For example, two or more groups of ribs may be provided, wherein the ribs within the group are parallel to each other, but an angle exists between the groups. Or all ribs have an angle among each other. As a result, particularly advantageous air flows can be adjusted.

From the above description it has become clear that the centrifuge 10 according to the invention has improved cooling to the extent that its space requirement is reduced, so that the centrifuge 10 can be kept more compact at the same Zentrifugierkapazität or at the same Baumaß Zentrifugierkapazität can be increased. In addition, a saving of components is possible and thus a saving of costs and assembly time.

Claims

claims

A centrifuge comprising a powered centrifuge rotor (13), a compressor cooling device (14), a housing (19) and a base plate (11; IIa; IIb), characterized in that the base plate (11; IIa; IIb) is in heat conductive connection with the compressor cooling device (14) such that the base plate (11; IIa; IIb) forms a heat exchanger of the compressor cooling device (14) and thus acts as at least part of a condenser (51) for the cooling medium of the compressor cooling device (14).

2. Centrifuge (10) according to claim 1, characterized in that the centrifuge is a laboratory centrifuge (10).

3. centrifuge (10) according to claim 1 or 2, characterized in that on and / or in the base plate (11; IIa; 1 lb) a conduit means (22; 50) is provided for the coolant, wherein the conduit means preferably as a pipeline (22; 50) is formed.

4. A centrifuge according to claim 3, characterized in that the conduit means (22; 50) is cast into the base plate (IIa) or that the base plate (IIb) is constructed at least in two parts (40, 41) and the conduit means (50) in the Dividing plane (T) between the two parts (40, 41) is arranged.

5. Centrifuge according to claim 4, characterized in that the conduit means (50) in at least a part (40, 41) of the base plate (IIb) is incorporated.

6. centrifuge (10) according to any one of the preceding claims, characterized in that the base plate (11; IIa; IIb) at least on one of the two major major surfaces (30, 31, 44, 45) at least one surface enlarging element (32, 33, 46, 47).

7. Centrifuge according to claim 6, characterized in that the base plate (11; IIa; IIb) one or more cooling ribs (32, 33; 46, 47).

A centrifuge (10) according to any one of the preceding claims, characterized in that the base plate (11; IIa; IIb) has at least one aperture (18) which is not in fluid communication with the conduit means (22; 50).

9. Centrifuge (10) according to one of the preceding claims, characterized in that at least one ventilation means (17) is provided in operative connection with the base plate (11; IIa; IIb), which is preferably adapted to direct an air flow in the housing (19). to produce the centrifuge (10), the side and / or bottom side enters the housing (19).

10. Centrifuge according to claim 9, characterized in that an air-permeable cover of ventilation openings (20, 21) in the housing (19) is provided.

11. Centrifuge according to one of the preceding claims, characterized in that the base plate (11; IIa; IIb) is arranged on the housing (19) of the centrifuge (10) such that the heat transfer between the base plate (11; IIa; IIb) and the housing (19) is interrupted or at least reduced.

A method of cooling a centrifuge, wherein a compressor cooling device (14) is provided, characterized in that a base plate (11; IIa; IIb) of the centrifuge (10) is used at least as part of a condenser of the compressor cooling device (14) the base plate (11; IIa; IIb) is in heat conductive communication with the compressor cooling device (14) such that the base plate (11; IIa; IIb) forms a heat exchanger of the compressor cooling device (14).

13. The method according to claim 12, characterized in that a laboratory centrifuge (10) is used as the centrifuge.

14. The method according to claim 12 or 13, characterized in that at least one ventilation means (17) is provided, which generates an air flow parallel and / or ascending through the base plate (1 1; I I a; I I b).

15. The method according to any one of claims 12 to 14, characterized in that a centrifuge (10) according to one of claims 1 to 1 1 is used.